1. This can only be done with a commercial product that mixes ice cream within a specially made ball with two chambers.
2. Fill the ice end with with ice and 1/2 cup of rock salt (3/4 cup if using the larger size ball) and close by hand.
- Standard ice cubes may not fit. You might need crushed ice.
- You’ll probably need at least 10 ice trays’ worth of ice.
3. Pour the ice cream mixture into the end with a metal cylinder. Leave an inch (2.5cm) at the top for expansion and close by hand.
4. Shake, roll, and pass the ball around for 10-15 minutes. The ball will probably be heavier than you expect.
5. Open the ice cream end with the plastic wrench that comes with the ball. Scrape the sides of the cylinder with a plastic or wooden spoon (metal will damage the cylinder). Close the lid by hand.
- Since the chamber is narrow and deep, stirring the ice cream might be difficult. If necessary, use the wooden handle of a spoon or spatula.
6. Check the ice end. Open the lid with the plastic wrench. Pour out any water and add more ice and up to 1/3 cup of rock salt. Close the lid by hand.
7. Shake, roll, and pass the ball around for 5–10 minutes.
8. Check the ice cream. Repeat the above steps as needed, or eat the ice cream as is.
- When you pour the ice cream out, be careful that it doesn’t spill into the raised decorative ledges and tight crevices; these may be very difficult to clean later on, especially if you use chocolate chips.
- The ice cream tends to be “soupy” in the middle and solid along the edges.